Rather attractive (6)
I believe the answer is:
pretty
This clue is a double definition.
'rather' is the first definition.
(synonyms)
'attractive' is the second definition.
(pretty can mean good-looking or attractive)
(Other definitions for pretty that I've seen before include "Film with Julia Roberts (belle)" , "Pleasing on the eye" , "Fair - fairly" , "Pleasing to look at" , "Reasonably" .)